Ernst & Young report argues that people will pay for premium content — just don’t try bundling

FarmVille

Upon beginning a farm, the player first creates a customizable avatar which may be changed at any point. The player begins with an empty farm and a fixed starting amount of ?farm coins?, the primary currency in the game. Players also earn XP (experience points) for performing certain actions in the game such as plowing land or buying items. At certain XP benchmarks, the player?s level rises. As the player obtains more items and progresses through levels, crops and animals become available to them via the ?market? where items can be purchased using either farm coins or ?farm cash?. Farm cash is earned by leveling up or completing offers, or purchased for real money.